The present invention relates, generally, to packaging machines. More particularly, the present invention relates to devices for applying glue to cartons on a packaging machine.
A common type of packaging machine processes a large volume of individual articles by arranging and grouping the articles, loading a group of articles into a carton, closing and sealing the cartons, and dispensing the loaded cartons to an area where they are consolidated for shipping. A typical carton is constructed of paperboard or corrugated paper and has flaps, which are folded, closed and sealed with glue.
The state of the art includes various devices for applying glue to cartons on a packaging machine. A common type of glue used to seal paperboard cartons is a hot-melt material. The glue is heated in a central container and pumped to individual dispensing stations. The dispensing stations and hoses between dispensing stations and the central container often are also heated to keep the glue at the proper viscosity for dispensing. Devices on the dispensing stations have at least one nozzle, and often have a plurality of nozzles through which the glue is applied to flaps of cartons or cartons as the cartons pass by the dispensing station.
Prior art devices for applying glue to cartons are believed to have significant limitations and shortcomings. The devices are often custom-made wherein the nozzles are in a fixed predetermined location. A custom-made device may be relative expensive. As carton size changes for different articles or different group configurations, the position of the flaps typically changes thereby requiring a change in the position of the nozzles on the dispensing station. A glue dispensing station on a packaging machine typically has a number of custom-made devices, each with different nozzle configuration for a specific carton configuration run on the machine. An inventory of several custom-made devices or a dispensing station is relatively expensive.
When a changeover is made on the packaging machine to run a different carton, one glue dispensing device is removed and another is installed. Such an operation can be time consuming and risk damage to the devices. The devices are hot from the glue, and care must be taken personnel are not burned when removing a device. The devices may be allowed to cool before removing, which takes time. Hoses between the glue supply and dispensing devices must be disconnected and reattached either to the devices or the to glue supply. This risks damage to the hoses each time a connection is changed. Air may also be undesirably introduced into the system by the new hose connection. The new hose and hoses must be heated to the working temperature before operation of the machine can be resumed, which increases changeover time. Such devices may be rather bulky, requiring a space of one or two linear feet of the packaging machine. On a packaging machine where space is limited, this basic requirement may be too much.
Other prior art gluing systems for packaging machine utilize a glue dispensing head attached to a clamping block that is moved in a vertical direction along a bar by a rack and pinion gear arrangement. In this prior art device, the bar has the rack teeth, and the pinion gear and attached pinion shaft are supported by the clamping block. The clamping block has an aperture receiving the bar. In this embodiment, an operator may turn an adjustment knob connected to the pinion shaft, which adjusts the vertical position of the clamping block and glue dispensing head relative to the bar. Rotation of the pinion shaft is selectively allowed or prevented by a locking knob threadably engaged with the pinion shaft. The clamping block is further secured to the bar by a screw in the clamping block which contacts the back side of the bar to provide a teeth engagement adjustment for the rack and pinion gear teeth by rotating the adjustment knob the glue head maybe raised and lowered. Disadvantages of this adjustment mechanism include a requirement of locating the rack and pinion or screw jack assembly on the front or operation side and rear or service side of the machine. This rack and pinion device requires adjustment not only on the operation side but also on the service side of the machine. Disadvantages of this glue had adjustment configuration include difficulty of adjustment on the service side of the machine due to lack of room for an operator. This arrangement increases changeover time. Additionally, the rack and pinion arrangement may not accommodate an accurate adjustment of the height which leaves the glue heads at a height which is out of specification. Additionally, the rack and pinion device includes a high number of parts arranged in a very complex manner. This arrangement therefore increases the likelihood of malfunction and increases the costs of the overall machine. Finally, due to the rather bulky nature of the rack and pinion apparatus, there is a significant likelihood that components of the adjustment apparatus or gluing mechanism may interfere with other stations or components on the packaging machine and become bound with one another causing damage to the machine.
Applicant""s invention overcomes the limitations and shortcomings of the prior art by providing an apparatus which utilizes a plurality of small, standard glue dispensing devices attached to automated adjustment mechanisms on the operation and service side of the machine. The apparatus and dispensing devices are cost effective.
The present invention relates to an automated adjustable apparatus for dispensing glue. The apparatus may include a glue head assembly for dispensing glue and an automated adjustment mechanism connected to the glue head assembly for adjusting a height of the glue head assembly to one of a plurality of predetermined heights. Each of the predetermined corresponds to heights of various carton configurations that receive glue for the purpose of gluing flaps to the carton.
In one embodiment of the present invention, the adjustment mechanism may include at least one servomechanism having a first end connected to a frame on a packaging machine and a second end connected to the glue head assembly. Although the servomechanism may comprise a number of devices, Applicant has found that automatically actuated cylinders having a predetermined number of extension positions work very well with the present invention. In other embodiments of the present invention, the assembly may include first and second glue heads wherein the first glue head is a position above the second glue head by predetermined separation distance. In the preferred embodiment of the present invention the adjustment mechanism is arranged and configured to increase the predetermined separation distance between the first and second glue heads with increasing overall assembly height adjustments. This feature allows for a greater distance between applied glue portions to accommodate greater distances between flaps on larger cartons.
In the preferred embodiment, the adjustment mechanism for the gluing apparatus may include a horizontally orientated servomechanism anchor bar that can support any number of servomechanisms connected to each one of the glue heads within the assembly. For example, in the preferred embodiment of the present invention, the adjustment mechanism includes a first servomechanism having a first end connected to the first glue head and a second end connected to the servomechanism anchor bar. The adjustment mechanism may also include a second servomechanism having a first end connected to a second glue head and a second end connected to the servomechanism anchor bar. In this embodiment, the first and second servomechanisms may independently position the first and second glue heads, respectively, to one of a plurality of predetermined heights to accommodate cartons of varying height.
In an alternative embodiment to the present invention, the assembly may include a third servomechanism connected between a relatively fixed point and a servomechanism anchor bar. The third servomechanism may be arranged and configured to extend the servomechanism anchor bar to one of a plurality of predetermined positions. In this alternative embodiment a total number of glue head positions would be equal to the product of the number of third servomechanism positions and the number of predetermined positions of the first or second servomechanisms.
The present invention includes many improvements over the prior art. First, the servomechanisms used in accordance with the present invention automatically move to one of a number of predetermined positions depending upon carton sizes. Thus, changeover time is significantly reduced because an operator need not adjust mechanisms on both the service and control side of the packaging machine. Additionally, since each one of the glue heights are predetermined automatically, an operator need not spend time attempting to adjust the glue head height to the proper specified position, which further reduces changeover time. Additionally, the servomechanisms used in connection with the present invention significantly reduced the part count associated with glue head height adjustment, thus, reducing overall cost of the packaging machine.
These and other features of the present invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings.